Flexible Magnetic Polymer Composite Substrate with Ba_1.5Sr_1.5Z Hexaferrite Particles of VHF/Low UHF Patch Antennas for UAVs and Medical Implant Devices

• Main Authors: Sang-Eui Lee, Seong Pil Choi, Kyung-Sub Oh, Jaehwan Kim, Sang Min Lee, Kang Rae Cho
• Format: Article
• Language: English
• Published: MDPI AG 2020-02-01
• Series: Materials
• Subjects: antenna substrate; magnetodielectric composite; hexaferrite; vhf; uhf; uav; mics
• Online Access: https://www.mdpi.com/1996-1944/13/4/1021
• ISSN: 1996-1944

Our goal is to fabricate flexible magnetic polymer composites as antenna substrates for very high frequency (VHF)/low ultra high frequency (UHF) antennas for unmanned aerial vehicles (UAVs) and medical devices. Magnetodielectric materials, which have permeability (<i>&#956;</i>) similar to permittivity (<i>&#949;</i>), have attracted great attention, because they facilitate miniaturization of microwave devices while keeping or enhancing electromagnetic characteristics. Mechanically millled Ba_1.5Sr_1.5Co₂Fe₂₄O₄₁ (Ba_1.5Sr_1.5Z) hexaferrite particles were used to increase permeability in the interesting frequency band. The microwave properties of Ba_1.5Sr_1.5Z composites were predicted and measured. Hansen&#8217;s zero-order analysis of antenna bandwidth and electromagnetic field simulation showed that the hexaferrite-based flexible composite could enhance a bandwidth and achieve the miniaturization of antennas as well. The magnetic antenna substrates can be a good solution to integrate antennas into the UAVs whose dimensions are comparable to or larger than communication wavelength.